On 2017/03/03 12:28 PM, wrote:
Mpfffff..... Some clarification required.

FINE silver plating (most of it) *will not* tarnish from exposure to air, nor will it form sulphur compounds - without other contributing factors. Sterling silver (.925 silver) is an entirely different matter.

What is going on here electro-galvanic (galvanic action) *corrosion* of the copper plating under the silver - and most things electro-silver-plated other than brass are first copper-plated to guarantee proper adhesion.

The black material noted is CuO, not tarnished silver.

Peter Wieck
Melrose Park, PA


Thanks, we've had many an Eprom with corroded legs that are from the
70s, in some cases the legs break off inside the IC sockets when the
EPROM is removed. Also this is common on some other ICs used in the
early 80s, such as Galaga which has Namco custom ICs, where again the
legs are corroding right off them.

Is there any way to arrest the process? Be nice to have something to dip
the legs into to cancel the corrosion, similar to using white vinegar
and water (50/50) to neutralize alkaline battery leakage corrosion.

John :-#)#

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